A study conducted by the Transportation Safety Board (TSB), on accidents involving airplanes equipped with floats reported 1432 accidents out of which 243 resulted in casualties. The study covered a 15 year period from 1976 to 1990. The 243 fatal accidents resulted in a total of 452 deaths. A more detailed investigation indicated that 41% of the deadly accidents happened during take-off while 37% happen during the approach and landing phases and these accounted for 103 accidents. These 103 accidents involved 276 occupants, passengers and crew, resulting in 168 casualties. Less than 10% of the survivors indicated having no problem evacuating the airplane. Unfortunately a significant number of casualties resulted from drowning while being trapped in the aircraft. This study highlighted the danger of operating sea planes and on the inherent problems associated with emergency egress from the confining fuselage following ditching.
A more comprehensive analysis of this data revealed a safety concern regarding some small aircraft equipped with floats. As required by the Pilot Operating Manual, 20° of flaps must be used for take-off. In this configuration it is extremely difficult to open the aft section of the right hand cargo door making the egress of the passengers located in the aft cabin extremely difficult. The egress problem is also aggravated by the cargo door opening mechanism which is difficult to operate. As a result, Transport Canada has reduced the authorized number of occupants to five for the aircraft. This imposes a severe restriction on aircraft operators and is believed to be of limited efficiency during emergency egress following ditching.
It is therefore an object of the present invention to provide a cargo door modification to facilitate emergency egress from a small aircraft.
It is a further object of the present invention to provide a modification kit which can easily be installed on the particular aircraft and which renders the same safer.
It is a further object of the present invention to provide a modification kit for the cargo door of an aircraft which is operational from both the interior and exterior while being inoperable during the take-off, flight and landing while being easily operable in emergency situations.
According to one aspect of the present invention, there is provided an aircraft door having a locking assembly, the improvement wherein said locking assembly comprises first and second locking members each having a distal end arranged to move between engaged and disengaged positions with respect to a frame portion about the aircraft door, a central actuator, each of the locking members having a proximal end connected to the central actuator such that in a central actuator first position the central actuator will cause the distal ends of the locking members to be in the engaged position while in a central actuator second position, the central actuator will cause the distal ends to be in the disengaged position, an exterior handle movable between an exterior handle closed position and an exterior handle open position, a first linkage extending from the exterior handle to the central actuator, the arrangement being such that when the exterior handle is moved from the exterior closed position to the exterior handle open position, the central actuator will move from the central actuator first position to the central actuator second position, an interior handle moveable between an interior handle closed position and an interior handle open position, and a second linkage extending from the interior handle to the central actuator, the arrangement being such that when the interior handle is moved from the interior handle closed position to the interior handle open position, the central actuator will move from the central actuator first position to the central actuator second position.
In greater detail, the first and second locking members may comprise any suitable; in a preferred embodiment, they comprise first and second rod like members which are designed to slide into and out of a recess in a door frame portion. However, it will be understood that they may engage any other portion of the aircraft and the term door frame portion would include any part of the aircraft which is located proximate the door. Similarly, other locking mechanisms such as hooks and the like may be used.
As aforementioned, the first and second locking members have a proximal end thereof which is secured to a central actuator. The central actuator in turn is connected to separate linkages which extend between the interior handle and the exterior handle respectively. Conveniently, the central actuator may comprise a pivotal member such that in a first position, the distal ends of the locking members are in an engaged position with the door frame portion while in a second position, the central actuator causes the locking members to be in a disengaged position with respect thereto.
The arrangement includes an exterior handle which is movable between an exterior handle closed position and an exterior handle open position. Conveniently, the handle may comprise a ring like member which may be pulled outwardly and then turned in order to move from the closed to open position. A key lock mechanism may also be supplied to securely lock the door when required. The exterior handle, as aforementioned, utilizes a first linkage, which, when the handle is moved from the opened to the closed position, will, through the linkage, cause the central actuator to move from the central actuator first position to the central actuator second position wherein the distal ends of the locking members move to the disengaged position.
The interior handle is also moveable between and interior handle closed position and an interior handle open position, with a second linkage extending from the interior handle to the central actuator such that when the interior handle is moved from the interior handle closed position to the interior handle open position, the central actuator, in a manner similar to that described to the exterior handle, will move from the central actuator first position to the central actuator second position.
In a preferred embodiment, the interior handle has a safety mechanism to prevent the handle being moved from the first position to the second position until the safety mechanism is disengaged. In one embodiment of the present invention the present invention, the safety mechanism comprises a portion of the handle which must be squeezed into position in order that the interior door handle can be moved from the locked to unlocked position.
As a further safety aspect of the present invention, it is preferred that the distance the handle must move from the first closed position to the second open position is substantial to prevent accidental opening thereof. In the case of a rotational movement, it is preferred that the rotational movement be in excess of 45° before the unlocking action will start.
In a preferred embodiment, there are provided first and second micro switches which are associated with the interior handle. A first micro switch would be associated with the safety mechanism and would advise the pilot that the safety mechanism has been engaged. A second micro switch would be associated with the movement of the locking members to an unlocked position.